Adiposity in Type 1 Diabetes

by Conway, Baqiyyah Nilija

Abstract (Summary)

Background: Increases in the prevalence of overweight and obesity states, and in their associated adverse health outcomes, have been well described in the general population. However, in type 1 diabetes (T1D), a disease traditionally characterized by a lean phenotype, time trends in overweight and obesity and the role of adiposity on complications in TID have not been well investigated. We therefore investigated time trends in overweight and obesity and the association of adiposity with mortality and coronary artery calcification (CAC), a subclinical marker of coronary artery disease in the Pittsburgh Epidemiology of Diabetes Complications cohort of childhood onset T1D.
Methods: Participants were first seen in 1986-1988 and followed biennially thereafter. Mortality was censored at January 1, 2007. Body mass index (BMI) was defined as kg/m² and Waist circumference (WC) was measured. CAC, visceral adiposity (VAT) and subcutaneous adiposity (SAT) by electron beam tomography. Free fatty acids (FFA) were determined by in vitro colorimetry.
Results: After 18 years of follow-up, the prevalence of overweight increased by 47%; the prevalence of obesity increased 7-fold. BMI demonstrated a quadratic relationship with mortality. Adjustment for waist circumference eliminated the increased risk in the obese. Weight gain was positively related to intensive insulin therapy and inversely with mortality. There was a positive relationship between the presence of CAC and adiposity measures, however the degree of CAC was not associated with any adiposity measure, except negatively with SAT in women. Finally, FFA were not associated with any adiposity measure and showed no association with CAC.
Conclusion: Adiposity is increasing in T1D and shows a complex association with coronary artery disease and mortality. These results have great public health significance by suggesting that avoidance of overweight, per se, in type 1 diabetes should not be a major priority; rather attention should focus on maximizing glucose control even though it may result in weight gain.